#define CPU_ONLINE		0x0002 /* CPU is up CPU已启动*/
#define CPU_UP_PREPARE		0x0003 /* CPU coming up CPU即将启动 */
#define CPU_DEAD		0x0007 /* CPU dead CPU死机*/
#define CPU_DEAD_FROZEN		0x0008 /* CPU timed out on unplug */
#define CPU_POST_DEAD		0x0009 /* CPU successfully unplugged */
#define CPU_BROKEN		0x000B /* CPU did not die properly */

kernel\cpu.c
#define CREATE_TRACE_POINTS
#ifdef CONFIG_HOTPLUG_CPU
#ifndef arch_clear_mm_cpumask_cpu
#define arch_clear_mm_cpumask_cpu(cpu, mm) cpumask_clear_cpu(cpu, mm_cpumask(mm))
#endif

#ifdef CONFIG_SMP
#define takedown_cpu       NULL
#endif /*CONFIG_HOTPLUG_CPU*/